1. Field of the Invention
The present invention relates to a seat adjuster by which the seat is adjusted its fore-and-aft position.
2. Description of Prior Art
In general, a seat adjuster for fore-and-aft adjustment of seat consists basically of a pair of movable rail and fixed rail, both of which are fitted together in a slidable manner, and a lock mechanism provided over the two rails for permitting locking unlocking of the movable rail against the fixed rail at a desired point along the longitudinal direction thereof. The movable rail carries a seat and fixed rail is fixed on a floor of the vehicle.
A concrete example of this seat adjuster is shown in FIGS. 1 and 2, which depict a conventional, vertically arranged type of seat adjuster. According thereto, there is provided a vertical-type slide rail (2) comprising a fixed rail (4) of a generally C-shaped configuration in section, which is fixed upon a floor of a vehicle (not shown) and a movable rail (3) fitted slidably via balls (5) within the fixed rail (4), whereupon the width-wise planes of both fixed and movable rails (4)(3) stand vertically in relation to a horizontal plane of the floor, as opposed to an ordinary flat-type slide rail.
To that movable rail (3), a seat cushion frame (1) is fixed, on which a seat cushion (c) is mounted. At the inner side of the frame (1), a shaft (8) is supported by a bearing member (7) in a rotatable way, the shaft (8) extending along the longitudinal direction of the frame (1). A lock pawl (6) is fixed to the shaft (8), with its forward end passing through the hole (1a) perforated in the frame (1).
As best seen from FIG. 2, the forward end of lock pawl (6) passes through a through-hole (3a) formed in the movable rail (3) and through one of plural lock slots (9) formed in the fixed rail (4), whereupon the slide rail (2) is in a locked state. The plural lock slots (9) are formed in an equidistant way from one another along the longitudinal direction of the fixed rail (4).
A spring (10) is provided on the shaft (8) to biasingly cause the shaft (8) to be rotated normally in a direction to cause the lock pawl (6) to be engaged in one of the plural lock slots (9).
Figures only shows the right-side seat adjuster, but though not shown, there is provided a left-side seat adjuster, hence constituting a pair of right and left seat adjusters in a way sandwiching the seat cushion (c) for bilateral locking/unlocking purpose to the seat against the fore-and-aft sliding of the movable rail (4).
At the forward end of the shaft (8), a link piece (11) is fixed, with its lower end directed downwardly.
A second link piece (12) is fixed on a left-side shaft (8') such that the piece (12) is disposed opposite to the first one (11) and directed upwardly.
A pull wire (13) is extended between the first and second link pieces (11)(12), with both ends of the wire (13) being each connected to the respective free ends of the first and second link pieces (11) (12).
The left-side shaft (8') is provided at its forward end with an operation handle (14) and disposed at the door side of the seat.
Designation (15) denotes a cushion frame for receiving the seat cushion (C), which is disposed between the two shafts (8)(8').
Operating the handle (14) results in causing synchronized, simultaneous rotation of the two link pieces (11)(12) about the respective axises of the two opposite shafts (8)(8') by virtue of the pull wire (13). Of course, the shafts (8)(8') are rotated overcoming the biasing force of the spring (10). Then, the lock pawl (6) is rotated in a direction to be disengaged from the lock slot (9), allowing fore-and-aft sliding adjustment of the seat. After having adjusted a position of the seat, release of the handle (14) allows the lock pawl (6) to be returned into engagement with another one of the lock slot (9) under the biasing force of the spring (10).
In that way, the movable rail (3) is unlocked and locked at desired point relative to the fixed rail (4), and thus the seat is adjusted in its fore-and-aft position.
However, in this vertically assembled type of seat adjuster, in case of the seat shown being disposed at the left-side half in the automobile in relation to the center thereof; namely, at the door side of the automobile, the operation handle (14) projects at a high level under the seat, adjacent to the door of the automobile. This poses a problem that an occupant, when entering into or getting out of the car, will stumble over the seat, with his or her foot or a lower part of clothes being hit or caught by the highly projected operation handle (14). Moreover, particularly if the seat is an assistant seat next to the driver's one, the door-side disposition of the handle (14) prevents access thereto from a driver on the driver's seat and the driver can not reach the handle (14) to adjust the fore-and-aft adjustment of the assistant seat. Yet further, as understandable from FIG. 2, during operation of the handle (14), the left-side link piece (11) is hindered its upward movement due to contact with the seat cushion frame (15).